Thread tension releasing devices



Aug. 26, 1958 H. RITTER ETAL THREAD TENSION RELEASING DEVICES Filed Nov.14, 1956 IN VEN TORS Herman R/ffer Adam P Steiner BY 74 241/ @w IXTTORNEY Fig.l

WITNESS United States THREAD TENSION RELEASING DEVICES Herman Ritter,Cranford, and Adam P. Steiner, Linden, N. J assignors to The SingerManufacturing Company, Elizabeth, N. .L, a corporation of New JerseyApplication November 14, 1956,-'Serial No. 622,061 Claims. Cl. 112-433This invention relates to sewing machines and more particularly to ameans for releasing'the tension of the sewing thread of the sewing,machine each vtime the Presser-bar is raised, and the invention has asits'primary object to provide an improved device of thisjcharacter.

Another object of the invention is to provide an improved adjustablethread tension releasing device, by use of which the time of initiationof thread tension release can be adjusted at will.

A further object of the invention is to provide an improved means by theuseof which the time of initiation of thread tension release can beadjusted without also changing the setting of the slack-threadregulator.

A still further object of the invention is to provide an adjustablethread tension release which is inexpensive to manufacture and which hasfacilities for easy adjustment.

With the above-and otherobjects in view, as will hereinafter appear, theinvention comprises the devices, combinations and arrangements of partshereinafter set forth and illustrated in the accompanying drawings of apreferred embodiment of the invention, from which the several featuresof the invention and the advantages attained thereby, will be readilyunderstood by those skilled in the art.

In the single sheet of drawings, which forms a part of thisspecification:

Fig. 1 is an elevational end view of a sewing machine embodying thepresent invention,

Fig. 2 is an elevational fragmentary sectional view taken on the line2-2 of Fig. 1, and

Fig. 3 is a perspective view of certain parts of the mechanism shown inFigs. 1 and 2.

The sewing machine illustrated has a work-support or bed 16, from oneend of which rises a hollow standard 17 of a bracket-arm having a head18 from which a face-plate (not shown) has'been removed. The head 18, ina well known manner, carries a vertically reciproeating needle-bar 19and a stationary presser-bar bushing 20 which receives a movablepresser-bar 21. The lower end of the presser-bar 21 carries apresser-foot 22 and the upper end of the presser-bar 21 is hollow,thereby accommodating a helical spring 23 and the lower end of a rod 24.The upper end of the rod 24 is held in place by an adjusting screw 26. Abracket 27, which is secured to the presser-bar 21 by means of a splitcollar and a screw 28, is provided with a second screw 29 and ahorizontally extending hole 31. The hole 31 receives one end of aslack-thread regulator bar 32, which is held in the hole 31 by the screw29. At its other end 33, the slack-thread regulator bar 32 passesthrough an aperture 34 in the head 18 and is bent downwardly, therebyfunctioning to control the sewing thread (not shown), which thread alsopasses between a pair of tension disks 36-37, forming part of a threadtension device 38 of a type somewhat similar to that shown in U. S.Patent No. 2,462,812. An L-shaped link 39 has a lower circular end 41loosely wrapped around the resser-bar 21 at a 2,848,966 Patented Aug.26, 1958 location directly below the bracket 27. The upper end of thelink 39 surrounds a lifting stud 42 carried by one end of an arm 43.Lifting the arm 43, in a known manner by means of a foot-pedal (notshown) or by means ofa hand lever 44, lifts the bracket 27, thepresser-bar '21, and the slack-thread regulator bar 3233. Adjust member53, and a clamp screw 54. The body member 52 is supported in the head 18of the sewing machine by means of a pivot-pin 56 which enters a hole 57formed at a central location in the member 52. An arm 58 of the member52, which extends to one side of the hole 57, has a projection 59 whichengages the small end of a beehive spring 61, of which the large endengages an inner surface of the head 18. Beyond the projection 59, thearm 58 is bent at right angles to form a finger 60 adapted to engage theinner end of a tension-releasing pin 62 formed as part of the threadtension device 38. The other end of the pin 62, in a well known manner,

releases the grip of the disks 3637 on the thread (not the clamp screw,54. The segmental member'53, in addition to having a pair of guides 6768which engage the sides of the arm 63, thereby maintaining the segmentalmember 53 upright and in line with the end of the arm 63, also has ahooked end 69 adapted to overlie and be engaged by an end 72 formed onthe end of the screw 28 which is carried by and extends beyond thebracket 27. Reference to Fig. 1 shows that the slotted head of the screw54 faces toward the open end of the head 18 and thus is easilyaccessible for loosening and tightening of the said screw 54.

In the past, adjustment of the time of initiation of thread tensionrelease in the type of machine herein shown has been accomplished byloosening a screw (equivalent to the screw 28) and moving the positionof a bracket (equivalent to the bracket 27). In previous machines, thishas not only adjusted the time of initiation of thread tension but alsomoved the slack-thread regulator bar (equivalent to bar 32) and thus itwas impossible to adjust the time of initiation of thread tensionrelease without also adjusting the slack-thread regulator. With thepresent arrangement the time of initiation of thread tension release canbe adjusted by loosening the screw 54 and adjusting the segmental member53 with respect to the end 72 of the screw 28. If it is desirable toadjust the slack-thread regulator 32 without also changing the time ofinitiation of the thread tension release, both screws 28 and 54 areloosened. Then the segmental member 53 is adjusted to compensate for anychange made in the location of the bracket 27.

From the above it is evident that there has been provided an improvedtension release lever 51 having an easily accessible adjusting screw 54by use of which the time of initiation of thread tension releaseadvantageously can be adjusted without changing the setting of theslackthread regulator bar 32 and by the use of which adjustment of theslack-thread regulator bar 32 can be effected while the time ofinitiation of thread tension release is maintained at its originalsetting.

Having thus set forth the nature of this invention, whatwe claim is:

1. In combination, a sewing machine comprising a head, a presser-barmovably supported in said head, a bracket adjustably held to saidpresser-bar, means for raising said resser-bar, a tension release leverpivotally supported in said sewing machine head, said tension releaselever comprising a body member and asegmental member, means adjustablysecuring said segmental member to said body member, and means carried bysaid bracket for engaging said segmental member and thereby moving saidtension release lever when said presser-bar is raised.

2. In combination, a sewing machine comprising a head, a resser-barmovably supported in said head, a bracket adjustably held to saidpresser-bar, means for raising said resser-bar, a tension release leverpivotally supported in said sewing machine head, said tension releaselever comprising a body member and a segmental member, said body memberhaving a threaded hole formed adjacent to the free end thereof, and ascrew carried in said threaded hole, the said segmental member having anelongated hole through which passes said screw, and means carried bysaid bracket for engaging said segmental member and thereby moving saidtension release lever when said presser-bar is raised.

3. In combination, a sewing machine comprising a head, a presser-barmovably supported in said head, a bracket adjustably held to saidresser-bar, means for raising said bracket and thereby raising saidresser-bar, a tension release lever pivotally supported in said sewingmachine head, said tension release lever comprising a body member and asegmental member, said body member having a threaded hole formedadjacent to the free end thereof, and a screw carried in said threadedhole, the said segmental member having an elongated hole through whichpasses said screw, a pair of guides engaging the end of said bodymember, and means carried by said bracket for engaging said segmentalmember and thereby moving said tension release lever when saidpresser-bar is raised.

- '4. In combination, a sewing machine comprising a head, a presser-barmovably supported in said head, a bracket having a split collar by whichit is adjustably held to said Presser-bar, a screw arranged to tightensaid split collar and having an end extending beyond the said bracket, aslack-thread regulator bar carried by said bracket, means for raisingsaid bracket and thereby raising said resser-bar and said slack-threadregulator bar, a beehive spring of which one end engages the innersurface of said head, and a tension release lever pivotally supported insaid sewing machine head, said tension release lever comprising a bodymember and a segmental member, said body member comprising two arms, aprojection carried by a first of said arms and engaging one end of saidbeehive spring, a finger formed as part of said first arm, said secondarm having a threaded hole formed adjacent to the free end thereof, anda screw carried in said thread hole, the said segmental member having anelongated hole through which passes said screw, a pair of guidesengaging the end of said second arm, and a hooked end, the hooked endoverlying the end of the screw which is carried by said bracket.

5. A tension releasing mechanism for a sewing machine having a needlethread tension device and a presserfoot and means for raising saidpresser-foot, comprising a pivot adapted to be supported on said sewingmachine, a body member pivotally supported on said pivot so that one ofits ends is disposed to engage said tension device, a segmental memberadapted to be disposed to be engaged by said means for raising saidpresser-foot, and means securing said body member and said segmentalmember together and providing for regulating the time of initiation ofthe tension release.

References Cited in the file of this patent UNITED STATES PATENTS954,858 Free Apr. 12, 1910

